Re: [PATCH v2 21/21] gpio: add GPIO controller found on Waveshare DSI TOUCH panels

[Dmitry Baryshkov]

On Sun, Apr 12, 2026 at 09:06:51AM +0800, Jie Gan wrote:
> 
> 
> On 4/11/2026 8:10 PM, Dmitry Baryshkov wrote:
> > The Waveshare DSI TOUCH family of panels has separate on-board GPIO
> > controller, which controls power supplies to the panel and the touch
> > screen and provides reset pins for both the panel and the touchscreen.
> > Also it provides a simple PWM controller for panel backlight. Add
> > support for this GPIO controller.
> > 
> > Tested-by: Riccardo Mereu <r.mereu@xxxxxxxxxx>
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
> > ---
> >   drivers/gpio/Kconfig              |  10 ++
> >   drivers/gpio/Makefile             |   1 +
> >   drivers/gpio/gpio-waveshare-dsi.c | 208 ++++++++++++++++++++++++++++++++++++++
> >   3 files changed, 219 insertions(+)
> > 
> > diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> > index dbe7c6e63eab..1b210c451151 100644
> > --- a/drivers/gpio/Kconfig
> > +++ b/drivers/gpio/Kconfig
> > @@ -805,6 +805,16 @@ config GPIO_VISCONTI
> >   	help
> >   	  Say yes here to support GPIO on Tohisba Visconti.
> > +config GPIO_WAVESHARE_DSI_TOUCH
> > +	tristate "Waveshare GPIO controller for DSI panels"
> > +	depends on BACKLIGHT_CLASS_DEVICE
> > +	depends on I2C
> > +	select REGMAP_I2C
> > +	help
> > +	  Enable support for the GPIO and PWM controller found on Waveshare DSI
> > +	  TOUCH panel kits. It provides GPIOs (used for regulator control and
> > +          resets) and backlight support.
> > +
> >   config GPIO_WCD934X
> >   	tristate "Qualcomm Technologies Inc WCD9340/WCD9341 GPIO controller driver"
> >   	depends on MFD_WCD934X
> > diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> > index 20d4a57afdaa..75ce89fc3b93 100644
> > --- a/drivers/gpio/Makefile
> > +++ b/drivers/gpio/Makefile
> > @@ -207,6 +207,7 @@ obj-$(CONFIG_GPIO_VIRTUSER)		+= gpio-virtuser.o
> >   obj-$(CONFIG_GPIO_VIRTIO)		+= gpio-virtio.o
> >   obj-$(CONFIG_GPIO_VISCONTI)		+= gpio-visconti.o
> >   obj-$(CONFIG_GPIO_VX855)		+= gpio-vx855.o
> > +obj-$(CONFIG_GPIO_WAVESHARE_DSI_TOUCH)	+= gpio-waveshare-dsi.o
> >   obj-$(CONFIG_GPIO_WCD934X)		+= gpio-wcd934x.o
> >   obj-$(CONFIG_GPIO_WHISKEY_COVE)		+= gpio-wcove.o
> >   obj-$(CONFIG_GPIO_WINBOND)		+= gpio-winbond.o
> > diff --git a/drivers/gpio/gpio-waveshare-dsi.c b/drivers/gpio/gpio-waveshare-dsi.c
> > new file mode 100644
> > index 000000000000..f4a1d4d3b872
> > --- /dev/null
> > +++ b/drivers/gpio/gpio-waveshare-dsi.c
> > @@ -0,0 +1,208 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2024 Waveshare International Limited
> > + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> > + */
> > +
> > +#include <linux/backlight.h>
> > +#include <linux/err.h>
> > +#include <linux/fb.h>
> > +#include <linux/gpio/driver.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/regmap.h>
> > +
> > +/* I2C registers of the microcontroller. */
> > +#define REG_TP		0x94
> > +#define REG_LCD		0x95
> > +#define REG_PWM		0x96
> > +#define REG_SIZE	0x97
> > +#define REG_ID		0x98
> > +#define REG_VERSION	0x99
> > +
> > +enum {
> > +	GPIO_AVDD = 0,
> > +	GPIO_PANEL_RESET = 1,
> > +	GPIO_BL_ENABLE = 2,
> > +	GPIO_IOVCC = 4,
> > +	GPIO_VCC = 8,
> > +	GPIO_TS_RESET = 9,
> > +};
> > +
> > +#define NUM_GPIO 16
> > +
> > +struct waveshare_gpio {
> > +	struct mutex dir_lock;
> > +	struct mutex pwr_lock;
> > +	struct regmap *regmap;
> > +	u16 poweron_state;
> > +
> > +	struct gpio_chip gc;
> > +};
> > +
> > +static const struct regmap_config waveshare_gpio_regmap_config = {
> > +	.reg_bits = 8,
> > +	.val_bits = 8,
> > +	.max_register = REG_PWM,
> 
> .max_register = REG_VERSION,
> 
> check comments in probe

Yep, thanks (and for other comments too)!


-- 
With best wishes
Dmitry